He accused the Chancellor of “kicking them in the teeth” after he announced self-employed workers paying the main rate of class 4 National Insurance contributions will see an increase by 1 per cent to 10 per cent in April 2018.

An 11 per cent increase in April 2019 will follow, altogether raising £145million a year by 2021/22 at an average cost of 60p a week to those affected.

“The self-employed had been seen as the great success story of the level of employment in this country, now you’re kicking them in the teeth,” Boulton told Jane Ellison on Sky News.